The present invention relates to ball nut and ball screw assemblies which incorporate ball nut attachments of one kind or another. Historically, exterior V-threads have been provided on one end of the nut to facilitate attachment, and the attachment has been provided with an opening having matching interior threads which enable the attachment to be received by the threads provided on the exterior of the nut.
For smoothness of operation, attainment of predicted life, and the elimination of potential binding due to side loading or moment loading on the ball screw, due to loads applied to the attachment, it has historically been necessary to tightly control the geometric tolerancing of the attachment element all the way back to the ball circle diameter. This was necessary because the longevity and smooth action of a ball screw is governed by the coaxiality of the applied load axis and the ball circle diameter centerline. The ball circle diameter may be described as the diameter of an imaginary cylinder, the surface of which passes through the centers of all of the load bearing balls in the helical screw groove.
The present invention, inter alia, is characterized by its elimination of this need to control the stack-up of tolerances in the assembly components which necessitated more precision machining and consequent expense.